DOCS: Separation of .dropdown and .dropup.
DOCS: Separation of .dropdown and .dropup.

BS3 commits: ebad91b9b591756c13123c6a0c648dd72ffda4f0

2947721120/googlebt4,todc/todc-bootstrap,aaroncnhk/todc-bootstrap,todc/todc-bootstrap,todc/todc-bootstrap,up2vs/todc-bootstrap,2947721120/todc-bootstrap,mozillo/todc-bootstrap,ztx1491/todc-bootstrap